Train-control system for railroads



March 26, 1929. c, LEAKE 1,706,856

TRAIN CONTROL SYSTEM FOR RAILROADS Filed Aug. 8, 1927 Patented Mar. 26. 1929.

UNITED STATES.

1,706,856 PATENT OFFICE.

RICHARD C. LEAKE, OF ROCHESTER, NEW YORK, lASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

TRAIN-CONTROL SYSTEM FOR RAILROADS.

Application filed. August 8, 1927. Serial No. 211,477.

This invention relates in general to railway traincontrol systems, and has more particular reference to an intermittent automatic inductive alternating current type of control system. a j

In one form of intermittent inductive train control system to which the present invention is applicable, a brake applying or train movement restricting device is controlled in accordance with traffic conditions ahead by means of inductively related trackway inductors and a carecarried receiver. In such systems it is most desirable that the neces' sary inductive c0-action between the trackway and car-carried devices take place with certainty and uniformity.

7 With the above and other objects in view, it is proposed, in accordance withthis invention, to provide an inductor and receiver of an improved type. a y.

More specifically, the invention provides a trackway inductor formed either of two par.

allel bars of magnetic material, or a single bar of magnetic material, with means for controlling it in accordance with the traflic conditions ahead, and a receiver comprising a core of rectangular annular for-1n carrying primary and secondary coils thereon in a particular relationship toeach other.

Further objects, purposes, and characteristic features will appear as the description of the invention progresses, reference being had to the accompanying drawings, showing solely by way of illustration, two embodiments of the invention. In the drawings Fig. 1 is a schematic showing of one form of the invention as applied to a train control system; and

Fig. 2 is a schematic showing of a modified form employing a difierent form of inductor. y j 7 Referring to. the drawings, and first to Fig. 1, a section of trackway is shown comprising track rails 1 separated into signalling blocks by means of insulating joints 2, each block havin a usual track battery 3 connected across t 1e rails at its exit end, and a wayside signal actuated at the entrance end and shown, in the present instance, as a semaphore type of signal. Obviously the signals.

could be of some other type, and the various controllingcircuits and devices'for the signals can be of any usual or desired form and hence it has not been deemed necessary to show or describe'them.

Positioned alongside the track, adjacent the entrance end of each block, is an inductor including, in the form of Fig. 1, two parallel bars 6 of magnetic material each of which is furnished with a coil 7 which coils are connected in series with each other and includedin circuit with a condenser 8 and contact finger 9 and front contact of the adjacent track relay. The condenser 8 is so chosen as to tune the inductor circuit for the frequency of alternating current employed in connection with the co acting receiver. Under clear traflic conditions in anyparticir lar block, the track relay for that'block will be energized so as to complete the circuit including the coils 7 of the inductor at the entrance end of such block, while under danger conditions this circuit will be opened at the contact finger 9 and front contactof the controlling track relay. While the control of the inductorshas been shown only for clear and danger, it is obvious that the inductor circuit could be controlled so as to be made under clear conditions, and broken under both. caution and. danger conditions, in any usual or desired manner, such for instances, as shown in the patent to V. K. Howe No. 1,60 i,098 of October 19, 1926, which employs a line relay controlled by the second block in advance of any particular inductor, to cause opening of the inductor circuit under caution conditions.

Carried on the car which is represented diagrammatically by axles and wheels 1.0, is a receiver including a rectangular, annular, core 11, carrying primary coils P and P and secondary coils S and Q Thecorc 11, as well as the inductor bars 6, is preferably made of laminated material, in order to cut down alternating current losses.

The primary coils P and P are connected in series with each other, and with a tuning condenser 12, and a source of alternating current 13, preferably of a frequency, higher than the usual commercial frequencies, such as 360 cycles per second, for-example.

The secondary coils S and S are likewise connected in series with each. other, with a tuning condenser 1.4, and a main control relay MR. The primary and secondary circuits just described are thus tuned for the frequency of i the alternating current supplied by 13.

The system includes an electro-magnetic device, or its equivalent, EPV, which is normally energized through acircuit including 'a source of energyi'lfi shown as a battery and a contact finger 16'and front contact of relay MR,.and-isjarranged toeit-her operatethe .usual car a1r brakes,-upon de-energization,

or. to impose any other desired train movement'restr ction. 1 As described above, the prlmary circuit 1ncluding. the primary coils P and P is co'ntinuously supplied with alternating Current,

ivhicl 'i-esults in magnetic flux bein pro 'dfu'c'ed the corle ll 'which travels through two separate paths, as indicated by'tlie dash line arrows ingFig gl, thus inducin'gvolta'ges in'the secondary'coils S and" S which are addit ve to ;,cause suificient current to flow through the secondary circuit including main 'relay M'R toy-normally energize such relay and maintaln the brake dev ce EPV 1n ener g ze'd"eoncl1t1o1i. I

V 'lh'etr'ackway inductors are positioned to be pa'ssed 'overby the car'carried receiver and 'toinduct-ively co-act therewith through an air gap, whereby to exert influences on the receiver in accordance witli'trafiicconditions througli the' entire length of the front and rearsides,respectively, of the core 11, then passjdownwardly to the end of the acent ar- '6,thr'ougli suehbar, and up 'fromthe 7 other end of such bar. back to the receiver Core 11', thus tending topauseflux tofiow through'the secondary C YOilsS andS 'in the "direction opposite; to the original" direction of flow.-- The paths followed by fiux, in the receiver, when unaffected by inductor, are

7 shown inFigs. 1 and 2, by dash line arrows, 1 {while the added paths for newer flux, when to pass therethrough in opposite directions, through separate paths, and' the' reluctances fofthese separate paths'are so adjusted by over an active (open'circuited') inductor,- are shown by; dotted line arrows in Fig. 2. Thus in "the caselof each secondary co1l,'flux tends .proportioning the inductor and receiver and fthe; s 'a'ace therebetween, as to make them {approximately "equal; these circumstances,the flux passing through the second ary coils S and: S is reduced to zero, or substantia'lly zero, thereby'to de-energize relay MR andcause' an automatic brake application dueto de energizat on of the" brake device i In theicas'e of the trainentering aclear block, the coils 7 of the inductor at the en trance to such block, are included in a closed circuit, and these coils 7 exert so great-a choking action against flux passingthrough the hars dfthat they oflFer practically no better pathi'va'y for fiux'ihan if the resultant "in {current substantially tozero.

luctances be unequal depending upon which ductor were entirely absent. Under such conditions, the receiver passes over the inductor without having any material change made in: the flux. distribution therein, and accordingly, the relay MR is not affected. Thus, on entering a clear block, no brake appl'i'catien'is incurred, but on entering a danger block, (or a caution block if such control he provided, as referredito above) on passing the signals at the entrances to such block, a brake application is incurred.

The form of'invention shown in Fig. 2, is 'diiierent from that just described only with respect to the trackwa inductor. This inductor 17 comprises a single bar, rathcrthan spaced para-llel'bars, and is positioned to be symmetrically arrangedbclow, and parallel with, the receiver, when 310:1!1333388 thereby, in the position shown in- Fig. 2; The control of the inductor 17, through its coir 17, by traffic conditions, isidentical with that of the first case, and its effect on the receiver with regardto the flux 'distrihution in the neceiver core, is substantiallythe same as above described; As shown in Fig. 2, the receiver is directly over theinductor 17, in its active, 'oropen,circuited, condition, with theqesulting change-in flux flow tendency as indicated by the dotted and dashed arrows in. such circumstances, relay MR is demergized, as is alsothe brake device EPV and thus a brake application is incurred.

From a consideration of the above described interaction between the receiver and an inductor in active condition, it will be seen that-by properly proportioning and adjusting the different elements, thereluetances oft-he alternative paths for the flow of magnetic flux-produced by theprin'iary coils l. and P can he made substantially equal, to thus reduce the resultant induced secondary If these repatlrh'as the greater reluctance, a small current, but insuflicient to energize relay M'R,

, will flow in the secondary circuit including this relay.

Instead of having the described inductors and receiver control brake control means which are absolute in their action, 'the system could include any usual acknowledging and reset devices, such, for instance, as shown in the Howe Patent 1,604,098, referred to-almve, whcrebyan acknowledging act wouldzpevmit the train-to pass a signal atstop or caution,

Without incurringa brakeapplieation and the reset device would be employed to restore the parts to normal afterthe incurrenoe of an automatic brake application due to failure to properly acknowledge on passing anactiue inductor;

The above rather specific description of one form-ofthe invention, is shown solely byway of example, and is not intended. in anyrmanner whatsoever, in a limiting sense. Ob-

viously, the invention can assume many different physical forms, and is susceptible of numerous modifications, and it is intended to include, in this application, all such forms and modifications as come within the appended claims.

Having described my invention, I now claim 1. In a train control system, a car-carried receiver including a closed loop core, two primary coils on the'core, positioned on opposite sides of the core and in staggered relation to each other, two secondary coils on the core, placed on opposite sides of the core and in staggered relation to each other, means for energizing the primary coils, and means controlled by the secondary coils for controlling train movement.

2. In a train control system, a car-carried receiver including a closed loop core, primary coils on the core, secondary coils on the core, means for energizing the primary coils with alternating current, means controlled by the secondary coils for controlling train movement, and an inductor, positioned in the trackway in inductive relation to said receiver core and coils and controlled in accordance with trafiic conditions ahead.

3. In a train control system a car-carried receiver including a closed loop core, two primary coils on the core, positioned on opposite sides of the core and in staggered relation to each other, secondary coils on the core, placed on opposite sides of the core and in staggered relation to each other, means for energizing the primary coils, means controlled by the secondary coils for controlling train movement, and an inductor, controlled in accordance with traffic conditions ahead, arranged to inductively affect the receiver.

4. In a train control system, a car-carried receiver including a closed loop core, two primary coils on the core, placed on opposite sides of the core and in staggered relation to each other, two secondary coils on the core, placed on opposite sides of the core and in staggered relation to each other, means'for energizing the primary coils, means controlled by the secondary coils for controlling train movement, and a single bar inductor, controlled in accordance with traffic conditions ahead, arranged to inductively affect the receiver.

5. In a train control system, a car-carried receiver including a closed loop core positioned in inductive relation to the road bed, primary coils on the core, secondary coils on the core, means for energizing the primary coils with alternating current, means controlled by the secondary coils for controlling train movement and a single bar inductor positioned in the road bed, controlled in accord ance with trafiic conditions ahead, and arranged to directly inductively affect the receiver.

6. In a train control system, a wayside inductor, controlled in accordance with trafiic conditions ahead, a car-carried receiver including an annular, substantially rectangular, core, primary coils on opposite sides of the core and in staggered relation to each other, means to energize the primary coils, with alternating current, secondary coils on the core arranged symmetrically with respect to the primary coils, and train movement restricting means controlled by the secondary coils.

7. In a train control system, a wayside inductor, in the form of a single bar of magnetic material, controlled in accordance with traffic conditions ahead, a car-carried receiver including an annular, substantially rectangular, core, positioned parallel with, and symmetrically to, the inductor, primary coils on opposite sides of the core and in staggered relation to each other, means to energize the primary coils, in series, with alternating current, secondary coils on the core arranged symmetrically with respect to the primary coils, and train movement restricting means controlled by the secondary coils.

8. In a train control system, a car-carried receiver including an annular, substantially rectangular, core, primary coils on opposite sides of the core and in staggered relation to each other, means to energize the primary coils, in series, with alternating current to cause flow of flux through the core, secondary coils on the core arranged symmetrically with respect to the primary coils, train movement restricting means controlled by the secondary coils, and traflic controlled means tending to at times cause a reversal in the direction of the flow of flux through the secondary coils.

In testimony whereof I aflix my signature.

RICHARD C. LEAKE. 

